No other applications are anticipated or have been submitted by us.
1. Background--Field of Invention
The present Electrical Plug Safety Cover relates generally to electrical plugs, and more particularly, to an attachable electrical plug safety cover adapted to prevent inadvertent exposure to the plug prongs as they are inserted into an electrical outlet to thereby protect the user against possible danger of electrical shock.
2. Background--Discussion of Prior Art
Typical electrical plugs include a plurality of electrically conductive prongs extending outward from the body for connecting to or plugging into a convenience outlet or like receptacle. If the electrical plug is not fully plugged in the prongs are partially exposed and may be energized. This produces a situation where a child or other person may couple the energized prongs by means of an electrically conductive material or touch the prongs simultaneously and induce an electrical shock. An electrical shock hazard also exists if a similar coupling or touching were to occur during the insertion of the electrical plug prongs into a convenience outlet or like receptacle.
In order to solve the problems, people have developed several kinds of safety plugs, prong covers and protective shields.
Examples of various safety plugs are disclosed in the following U.S. Pat. No. 2,082,986 to Staley in 1937; U.S. Pat. No. 2,396,901 to Tiffany in 1946; U.S. Pat. No. 2,423,250 to Modrey in 1947; U.S. Pat. No. 3,167,373 to Kostich in 1965; U.S. Pat. No. 3,513,435 to Degaetano in 1970; U.S. Pat. No. 3,575,684 to Mcintyre in 1971; U.S. Pat. No. 3,754,205 to Lenkey in 1973; U.S. Pat. No. 3,839,697 to Obert in 1974; U.S. Pat. No. 4,340,267 to Nukaga in 1982; U.S. Pat. No. 4,445,739 to Wooten in 1984; U.S. Pat. No. 4,820,176 to Niikura in 1989; U.S. Pat. No. 5,030,119 to Lowe in 1991; U.S. Pat. No. 5,046,961 to Hoffman in 1991; and U.S. Pat. No. 5,252,082 to Hsieh et al. in 1993. All of these share several common features. A retractable prong cover(s) either retract into an outer casing or retract along the exterior of the outer casing. Retraction along the exterior of the outer casing can be interfered with by the operator's grasp of the electrical plug during insertion into a convenience outlet or like receptacle. Most embodiments show the safety plugs connected directly with an electrical cord by mechanical means. Connection of the safety plug in this manner to an existing electrical plug and cord would require cutting off the existing one-piece standard electrical plug from the electrical cord, and reconnecting the electrical cord wires to the safety plug in a manner which is not usually as strong as a standard one-piece molded electrical plug nor as resistant to becoming disconnected from the safety plug if the safety plug is unplugged by pulling on the electrical cord. Other embodiments of the safety plugs show them functioning in a manner similar to an adapter. A standard electrical plug is inserted into the back of the safety plug adapter and the combined assembly is plugged into a convenience outlet or like receptacle. The electrical plug can become partially unplugged from the safety plug adapter and present the same electrical shock hazard that would be present if the safety plug adapter was not attached at all.
Examples or various prong covers are disclosed in the following U.S. Pat. No. 3,147,055 to Rubens in 1964; and U.S. Pat. No. 3,631,320 to Eckert in 1971. In Rubens the cover is held onto the prongs by friction. Over a period of time as material creep and failure of material elasticity occurs, this frictional connection will fail resulting in the prong cover becoming separated from an unplugged electrical plug. In Eckert a base plate which the prong covers are secured to is shown fitting into a recess on the electrical plug's face. Modern, one-piece, molded electrical plugs have no such recess.
Examples of various protective shields are disclosed in the following U.S. Pat. No. 2,458,153 to Festge in 1949; U.S. Pat. No. 2,759,160 to Kelly in 1956; U.S. Pat. No. 3,258,732 to Martin in 1966; U.S. Pat. No. 3,740,694 to Fisher in 1973; U.S. Pat. No. 3,763,457 to Whippo in 1973; U.S. Pat. No. 4,305,634 to Lewis in 1981; U.S. Pat. No. 4,391,481 to Golden in 1983; and U.S. Pat. No. 4,810,199 to Kar in 1989. All of these, except for Lewis, share a couple of features. A resilient, flexible shroud is frictionally secured either to the electrical cord, as in Golden; to the electrical plug body, as in Festge, Kelly, and Martin; or to the prongs, as in Fisher, Whippo, and Kar.
Modern one-piece molded electrical plugs usually have a flange on the prong face which is several times larger than the attached electrical cord. This flange makes it virtually impossible to connect a shroud secured by friction to the electrical cord unless one disconnects the electrical cord from its appliance and slides the shroud down the electrical cord to the electrical plug. Such an assembly operation would require additional tools and a specialized knowledge of the appliance's inner electrical connection points.
Shrouds secured by friction to the electrical plug body require different sizes for the different sized two-prong and three-prong electrical plugs currently manufactured. Once again, the electrical plug flange makes slipping the shroud onto the electrical plug body difficult.
Shrouds secured by friction to the electrical plug prongs require the flexible shroud material to either bunch-up between the electrical plug face and the receptacle, flare out from the electrical plug during insertion which produces a fairly strong unplugging force to be exerted by the shroud, or requires the shroud to roll back around the electrical plug body where it interferes with the operator's grip on the electrical plug or allows it to get hung up on the flange and thus not cover the prongs when the electrical plug is unplugged.